RESTRICTION ENDONUCLEASE MAP VARIATION AND GENE ACTIVITY IN THE ADH REGION IN A POPULATION OF DROSOPHILA-MELANOGASTER

Variation within a 12 kb [kilobase] region containing the Adh gene was studied in 16 highly inbred lines of independent extraction from a population of D. melanogaster, Texas. Out of a selection of 8 hexanucleotide specific restriciton endonucleases, 4 restriction site and 5 DNA insertion/deletion variations were observed and the heterozygosity per nucleotide was 0.004. Linkage disequilibrium between 2 restriction sites, considerably removed from and on either side of the Adh transcriptional unit, identified 2 major classes of chromosome or haplotype in the population. These 2 haplotypes were strongly associated with the capacity of lines to respond to the environment (genotype-environment interaction) in ADH [alcohol dehydrogenase] activity. A control or regulatory polymorphism was present in the population in association with the Adh transcriptional unit.